Science Safety

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Chapter 8

Accident Prevention and Safety Management

Planned Accident Response
Eye Hazards
Fires
Field Trips

Planned Accident Response

Accident implies damage and injury or the potential for damage or injury. The purpose of any action taken at an accident is to minimize the effect of the accident. If action must be taken quickly, does the school's science laboratory have a Planned Accident Response?

It involves

  • being aware of the continued dangers to people and property in the accident environment
  • knowing the extent of injury to people involved in the accident
  • knowing the resources available for coping with the accident
  • assessing the results before action is taken

A Planned Accident Response can greatly reduce the time for decision making. A Planned Accident Response means being familiar with the resources (knowledge, personnel, and material) available for reducing the effects of an accident, maintaining resources regularly, and understanding the steps for a rapid organized response to an accident. To take action quickly, prepare in advance for the accident potential of any planned activity.

The action taken depends on the circumstance. Some common requirements for successfully coping with any accident are to

  • appoint one person with absolute control of the actions taken by all people at the site (if necessary, send for qualified help; the one who goes for help should report back to the leader)
  • recognize and reduce immediately life-threatening conditions (this may just mean clearing everyone from the area)
  • initiate a quick assessment of an injury and take appropriate action (do only the things you have been trained to do; leave extensive treatment to the medical experts)
  • make the accident environment safe (fire, electrical, and toxic material hazards can be reduced by shutting off gas and power, ventilating, and using protective gear ­- a safe approach to the accident area must be well thought out)
  • assign preliminary investigation of the accident to one person
  • take initial notes before clean-up starts
  • investigate thoroughly every accident and prepare written recommendations for the prevention of similar accidents

Accidents are symptoms of a problem and if an accident happens once, it can happen again. Accidents can be prevented if the problem is uncovered and corrected. The way to prevent the recurrence of an accident is to discover and eliminate the conditions that led to the accident.

It is easy to take a superficial view of an accident, especially if the result is minor. The result may not always be of little consequence, however, even for the same type of accident. Accident investigation must

  • begin before clean-up is done
  • be done by someone who is familiar with investigative procedures
  • produce a written report that follows a standard, simple format

Accident investigation report format includes

  • describing the accident objectively
  • describing the accident result
  • describing the action taken at the accident
  • describing the root cause(s) of the accident
  • recommending action to prevent recurrence

Investigate and write a report even if there is no injury (see Appendix E for a sample accident investigation report).

To reduce accident frequency, students as well as teachers must be aware, alert, and willing to act. Address student safety awareness and attitudes frequently. A thorough discussion with students should be part of the follow-up action.

Of 33 accidents of the same type only about three normally result in injury. Of the three injuries, one can be expected to be serious.

Accident Policy

Accident prevention requires the recognition of accident potential. When an accident occurs, the ability to minimize the effect of the accident requires a Planned Accident Response. Teachers in charge of laboratories must

  • possess safety training that addresses both accident prevention and accident response
  • provide safety education to the students to raise awareness of accident potential and work towards a safety-conscious attitude
  • conduct a thorough investigation of every accident, however minor, and write a report that objectively describes the accident, the results, the primary and secondary causes, and make recommendations of action to be taken to prevent recurrence of the accident

Teaching About Accident Prevention

Safety and accident prevention should be reinforced throughout the year by teachers modelling and students demonstrating safety-consciousness.

Suggested Lesson Plan

Objective: To develop a safety-conscious attitude in students.

Placement: Before the first lab session with continuous reinforcement throughout Middle and Senior Years.

Activities include

  • illustrating the web of events that can lead to an accident, using a simple example, based on an actual accident report (see Appendix E). No one event is usually the cause of an accident, rather a combination of apparently harmless events occurs and the accident happens
  • using the Lab Safety Program from Fisher Educational (slides, cassette, manuals, and a film, Safety: Isn't it Worth it?) as an information base that can be referred to frequently
  • using safety items in every quiz, especially lab quizzes

Eye Hazards

The eye is probably the most vulnerable and easily damaged part of the body. It is also an important link between the individual and the outside world. Every effort should be made to protect eyes.

The eye is protected from impact injuries by a bony socket, which intercepts large objects before they reach the surface. Tears provide lubrication for the eyelids and wash foreign materials from the surface of the eye. The eyelids close to protect the surface of the eye from damage by small objects. The fatty tissue lining the bony socket cushions the eye against shock.

Despite these defences, the eye is easily damaged. The eye is a complex, specialized organ which does not recover as other tissues do from injury. The eye possesses relatively few blood vessels. Consequently, injuries are much slower to heal and the eye may not fully recover.

Foreign bodies present the most common danger. Particles can lodge on the surface of the eye where they are generally irritating. Sharp objects can penetrate deeply into the eye where they may cause no pain after the initial trauma. Certain types of particles can be extremely damaging (e.g., pure copper and iron particles which might penetrate the eye could result in the loss of sight because of their toxic effects on the tissue).

Flying glass (from an exploding test tube or flask, or from glass tubing breaking while being inserted into a stopper) can also cause severe eye injury.

Laboratory procedures that can generate liquid droplets or splashes include pouring, stirring, blending, heating, and reacting of chemicals. Glassware cleaning and accidental breakage can also cause chemicals to reach the eye.

Another hazard found in the school science laboratories is radiation. Ultraviolet, visible, and infrared radiation damage eye tissue if the intensity level is sufficiently high. The increasing use of lasers requires special eye protection in addition to special facilities and proper techniques.

Eye Protective Devices

Class 1 ­ Safety Glasses

These consist of safety lenses in a special frame which supports the lenses around their entire periphery. Safety glasses are commonly used with sideshields. Lenses must not be made of glass, but either plastic or polycarbonate, depending on the degree of impact protection needed. These are not adequate for experiments involving chemicals.

Class 2 ­ Eye-Cup Goggles

These consist of two cups, with lenses and lens retainers connected by an adjustable bridge and a replaceable headband. Eye-cup goggles differ from each other mainly in the type of ventilation provided (see Class 3 for types).

Class 3 ­ Monoframe Goggles

These goggles consist of a flexible frame forming a lens holder or a rigid frame with integral lens or lenses having a cushioned fitting surface on the full periphery of the facial contact area. A headband or other support retains the frame comfortably in place. The goggles may be ventilated, in which case the openings must not provide a direct route for chemical or physical agents to reach the eyes. Subclasses include

  • Chippers' models providing protection against impact from flying objects.
  • Dust and Splash models providing protection against relatively fine dusts, fumes, liquids, splashes, mists, or sprays, and impact.
  • Welders' and Cutters' models providing protection against glare, injurious radiation, and impact (the lens mount must be opaque to the radiation [UV, IR, or visible])

Class 4 ­ Welding Helmets, Class 5 ­ Hand Shields, Class 6 ­ Face Shields, Class 7 ­ Non-Rigid Helmets (Hoods)

These classes are unlikely to be needed in science classrooms. For more information contact the Canadian Centre for Occupational Health and Safety.

An ultraviolet sterilization cabinet should be obtained and used to reduce risks of eye and skin infections being transmitted between students using glasses or goggles. Metal UV cabinets are available with timers and safety door switches to prevent opening when the UV light is on. One cabinet may meet the needs of several science classes.

Adapted from Eye Protective Devices, Manitoba Association of Optometrists. Used with permission.

Eye Protection Policy

A basic tenet of any eye protection policy should be a statement such as "approved eye protection must be worn at all times by everyone in a laboratory situation using chemicals, explosive materials, compressed gases, hot liquids or solids, injurious radiations, electrical discharges, or other unidentifiable hazards."

Contact Lenses

In the past, some school authorities have banned contact lenses from school laboratories. Information provided by the Manitoba Association of Optometrists, however, shows that there is a relative lack of documentation on the harmful effects of wearing contact lenses in scientific workplaces. Some types of contact lenses may give added protection to lens wearers in instances of splash, dust, flying particles, and non-ionizing radiation.

Contact lenses offer additional advantages that could

  • improve performance in rain or mist (e.g., during field trips)
  • eliminate lens reflections or fogging
  • eliminate mechanical interference with instruments such as microscopes
  • eliminate broken lens hazard
  • reduce perspiration-related problems
  • eliminate lens greasing, smearing or dust
  • harmonize with safety equipment
  • increase visual field (no image jump)
  • improve visual treatment in some cases (high myopia)

These factors should be considered before a ban is declared.

An evaluation of the risks involved is best done by the student, the student's family, and the practitioner who prescribes the contacts. Many varieties of contact lenses are available: hard versus soft, gas permeable, extended wear, and disposable versus semi-disposable. It is difficult for a school policy to stay abreast of all these considerations. The school and the science teacher(s), however, must be informed of the student's decision (see Appendix C).

The student handouts can serve for discussion and review of correct procedures.

Teaching About Eye Hazards

Teachers should caution students about eye hazards and appropriate procedures to avoid injury. Teachers should ensure that students wear appropriate goggles in the laboratory.

The eye's natural defences are much less effective mechanisms than the self-cleansing ability of the lungs, or the self-healing properties of the skin. The eye requires artificial defences, and immediate medical attention if injury occurs. Show students how to protect their eyes by

  • showing audiovisual material on eye safety
  • administering an eye safety quiz
  • making sure students with contact lenses are identified

Student Handout: Eye Safety

General Protection

  • Eye safety must be of primary concern during any laboratory procedure. Remember to protect your eyes at all times. This should be more important than any other concern.
  • Become acquainted with the location of the eyewash facilities in each of your science classrooms. Learn how to use them correctly. To prevent permanent injury from most chemicals, the eyes should be flushed for about 15 minutes with continuously running water .
  • In chemistry or biology labs, use goggles with splash-proof vents which prevent liquids from reaching your eyes.
  • In labs with mechanical hazards (e.g., machinery), wear suitable shatter-resistant safety glasses (with side and top protection) or goggles.
  • In labs with radiation hazards (IR, UV, lasers), wear goggles that filter out the radiation.
  • When placing safety glasses or goggles down on a surface, do not place the glasses with lenses touching the surface. This will cause the lenses to become scratched, thus reducing the visibility through the lenses and increasing the risk that the lenses can break. Place glasses or goggles with the lenses not touching a surface or place them in a protective case.
  • Do not stare directly at any bright source of light (e.g., a burning magnesium ribbon, welding torches, lasers, or the Sun).
  • You will not feel any pain if your retina is being damaged by intense radiation. Do not rely on sensation to protect you.

Contact Lenses

  • If you wear contact lenses, check with your optometrist for advice about wearing them during chemistry experiments.
  • Contact lenses are safe if splash-proof goggles are worn during any experiments involving liquids, glass manipulation, or any similar risks.
  • Make sure your teacher is aware if you are wearing contact lenses and indicate the type (extended-wear, disposable, hard, or soft). Complete the information sheet provided.
  • Let your teacher know if your status regarding contact lenses changes during the school term. A form is available for this purpose.

Fires

Burning is the rapid oxidation of a fuel by an oxidizer (usually air) with the liberation of heat and (usually) light. A fire can be started when sufficient energy is present to initiate the reaction. The process of burning involves the three interrelated components: fuel, oxidizer, and energy source. These three components make up the fire triangle. Removal of at least one side of the fire triangle is the basis of fire control and safety.

Sources of Fires

Fire has always been one of the attendant hazards of laboratory operation. Laboratories make use of flammable materials including solids, liquids, and gases. Common sources of fire hazards in school laboratories are

  • solvent vapours
  • reactive chemicals
  • uncontrolled chemical reactions
  • inadequate storage and disposal techniques
  • heat due to electrical faults
  • loose clothing and hair
  • misused gas cylinders
  • inadequate maintenance
  • built-up static electricity
  • inapproriate laboratory design
  • solvents stored in areas with inadequate temperature control

Fire Extinguishers

The type of fire and extinguisher used are related. Learn the different classes of fire and the proper extinguisher for each class. An extinguisher may act on any or all of the three sides of the fire triangle to extinguish the fire. Usually an extinguisher either cools the area so a fire will not burn (remove energy source) or smothers the fire (removes oxidizer) or both.

Fire Extinguisher Location and Condition

They must be

  • maintained in operable condition and completely checked at least annually
  • recharged after every use
  • marked clearly as to class and use
  • located conspicuously and marked with signs
  • mounted at an accessible height, preferably near an exit door or near the area of use
  • checked monthly

The following table describes appropriate applications of fire extinguishers.

Fires and Fire Extinguishers
Fire Classification Fire Extinguisher
Class A ­ Fires involving ordinary combustible materials such as wood, cloth, paper * Use water (dry chemical extinguisher can also be used)
Class B ­ Fires involving flammable liquids such as solvents, greases, gasoline, and oil * Dry chemical foam, CO2
Class C ­ Fires involving electrical equipment * Non-conducting agents (e.g., dry chemical or carbon dioxide)
Class D ­ Fires involving combustible metals such as magnesium, sodium, lithium, powdered zinc * Special dry powder medium or dry sand

 

Fire Safety Equipment

Every school laboratory should be equipped with firefighting devices including

  • a fire blanket (made of fire-proofed wool/rayon material or woven fibreglass) not to be used where spillage and fire spreading is possible, mounted low enough so it can be reached by a person lying on the floor
  • a sand bucket and scoop ­- useful for small fires of all kinds
  • an adequate number of suitable fire extinguishers
  • teachers trained in the correct use of the appropriate equipment

Dealing With a Small Fire

  • ask all students to keep away immediately (the teacher alone should deal with any fire)
  • leave to burn out if only a small amount remains to burn and flames are unlikely to ignite other materials
  • wear a face shield, heat-resistant gloves, and place a fire-resistant cover over the fire if more than a small amount remains to burn (avoid breathing fumes)

Do not

  • throw water over a chemical fire
  • use a fire extinguisher on standing beakers and flasks
  • turn on water after a flaming container is placed in a sink

A Fire Safety Policy

Due to the frequent use of flammable materials in laboratories, the potential for extensive property damage and severe personal injury is very high. The goal of every science teacher should be to reduce the chance of fire to the lowest probability possible.

A successful fire control program includes

  • training individuals in the hazards of fire
  • designating lab procedures
  • maintaining chemical storage facilities
  • maintaining effective fire control equipment

Suggested Procedures

  • do not stock large quantities of solvents (order enough for one year's use only)
  • rehearse experiments students will perform and use minimum quantities of materials
  • store solvents in an approved (UL, CSA) fire resistant cabinet
  • store oxidizers and reducers separately

Teaching About Fire Safety

Teachers should reinforce the dangers of fire in a laboratory setting.

Suggested Lesson Plan: Fire Safety

Time: 2 periods

Placement: Lab Safety Orientation (Kindergarten­Senior 4)

Senior 1 Science ­ Chemical Interactions

As indicated, many of the substances used in a science laboratory are flammable and need careful attention. Burns are common injuries suffered in labs and there is a need to be cautious. Illustrate the dangers involved and control procedures by

  • burning a small amount of methanol in an evaporating dish in the fume hood (turn the lights off to see the blue flame and then extinguish by placing a watch glass over the evaporating dish)
  • showing the film 28 Grams of Prevention (Fisher Scientific Company)
  • demonstrating the use of proper fire extinguishers with certain classes of fires
  • demonstrating proper use of fire blankets, showers, eye wash, and fire escape procedures

Field Trips

The benefits of field trips are often significant. Long after students complete a science unit, they may recall the field trip as one of the highlights of their experiences. Whether the trip involved an afternoon at the local nature centre or a week on a camping trip, it is special. The routine of school life is broken, and students have an opportunity to explore the natural world.

For the teacher, however, the field trip represents a myriad of logistical challenges which must be dealt with long before the event. Each of these challenges has at its root a potential safety problem. If not dealt with appropriately, the consequences of incomplete planning could be disastrous. A checklist can be found in Appendix F.

The primary purpose of a science field trip is to investigate applications of science or to explore some aspect of the natural environment. Field experiences may be classified in two groups: local and remote. Local trips are usually of one day or less and involve a facility such as a museum, zoo, factory, research centre, or postsecondary institutions. Remote field trips often involve outdoor experiences: a bicycling trip through the Whiteshell Provincial Park or a hike to investigate sand dunes in Spruce Woods Park. The element of risk is greater outside, and, consequently, the need for thorough planning is essential.

Local Field Trip

One concern is transportation. Problems are minimized if all students travel together in a bus. If teachers, parents, or students, however, drive other students in private vehicles, find out what liability coverage the school division provides for the drivers, and what minimum coverage the drivers themselves must have to comply with division policies. Some divisions have a form for volunteer drivers to sign.

Does the site itself pose any special hazards? Question the contact person at the site before you arrive, and let your students know about the hazards before you set out and again upon arrival.

Obtain written permission from parents before taking students on any field trip (see a sample checklist for preparing letters to parents, and a Parent Permission Form and Field Trip Medical Information Form in Appendices F, G, and H, respectively).

Adequate supervision is important. Ask the contact person at the site about what adult/student ratio is desired. The ratio varies depending upon the age and number of students, and the site. Students are safer and your host is likely to be more receptive to future visits if adequate supervision is maintained.

Remote Field Trip

The factor which makes this trip special is that it usually involves a more remote wilderness destination than a local trip. You should

  • discuss the trip with your principal
  • outline the trip to your students
  • obtain written parental permission (disclosure letter)
  • obtain any important medical information (see Appendix F)
  • ensure proper liability insurance coverage is provided for all drivers

A major concern for many educators is teacher and school board liability in outdoor field trips to remote or wilderness areas. The Public Schools Act indicates that the discipline in every school be that of a kind, firm, and judicious parent. It follows that a similar standard of care is expected on field trips.

In addition, if the teacher has some special expertise (e.g., training as a canoe instructor or gymnastics teacher) the teacher is expected to exercise that skill while instructing and supervising students in these activities. If a teacher fails to exercise such skills or care, and a student is injured as a result, the teacher and the school board may be liable for negligence.

Factors to be Considered

  • Is the activity suitable to the age and condition (mental and physical) of the student?
  • Has the student been progressively trained and coached to do the activity and avoid the foreseeable dangers?
  • Is the equipment being used adequate and suitably arranged?
  • Is the activity, particularly if it is inherently dangerous, being properly supervised?

Teachers and administrators must assess these criteria when determining the types of outdoor activities. An important factor is the level of qualification possessed by the leader and other adults on the trip. Adults leading trips into wilderness areas must have current first aid certification. One member of the group should have CPR (cardiopulmonary resuscitation) training. St. John Ambulance or Canadian Red Cross provide both types of training (see Appendix J).

Leading students in wilderness areas of Manitoba takes more than just common sense. The leader must have visited the area before taking students. Students should be prepared in terms of environmental conditions. Information to assist teachers in planning field trips may be found in Beyond the Classroom: A Guide to Outdoor Education, Outdoor Education Resource Catalogue, and Winter Activities (see the Bibliography).

Travelling to the U.S.

If your field trip will take you to Bemidji, Grand Forks, Minneapolis, or other sites in the United States, investigate two health/safety issues:

  • What liability coverage does your school division/distict provide for you while in the U.S.? (Call MAST for information on Blue Cross coverage)
  • What health coverage do you and your students need should you be hospitalized while in the U.S.?

Many students, upon checking with their parents, will find they have an "Extended Medical Benefit" package with their health insurance (those without this coverage may wish to purchase a short-term travel health policy with a private agency).

Inform parents of this added concern in your disclosure letter. Should a student be hospitalized in the U.S., the parents will appreciate the opportunity to prepare for the expenses incurred.